Abrasive disc holder



April 13, w48.` G. A. QLSEN I 2,439,751

ABnAsIvE DIscv HOLDER Filed July 13,1946

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IN VEN TOR. @a mfaww Patented Apr. 13, 1948 UNITED STATES PATENT OFFICEABRASIVE DISC IHOLIERl Gustav A, Cisen, Sioux City, Iowa,` assignor toAlbertson & Company, Inc., Sioux City, Iowa.

a corporation of Iowa Application July 13, 1346, serial No. 683,523

6 Claims. (Cl. 51-197) This invention relates to abrasive disc h'oldersof the kind widely employed by automobile body finishers and others forsmoothing rough surfaces; and it has to do more especially with animprovement in the type of abrasive disc holder described in UnitedStates Patent 2,132,917, granted to F. O. Albertson October 11, 1938.

In the holder of the Albertson patent the abrasive disc is securedagainst a resilient hard rubber pad which affords a certain amount ofilexibility at and near the periphery of the discwhich flexibility isvery essential to good results, but is not adapted to cushion shockcomponents transmitted through the disc in the plane of rotation.

My object is to improve the performance characteristics of abrasive discholders, such as that described in the Albertson patent, to the end ofachieving smoother operation and reduction of shock, and, by so doing,to provide an equipment which will turn out a better job and, generally,with concomitant saving of time.

, I have found that the above-stated object substantially can berealized by incorporating in the hub of the disc holder suitableresilient means which serve to introduce a limited yieldability near theaxis of rotation, both in the plane of rotation and all planes normalthereto, with the result that the abrasive disc is better able to copewith unusually irregular surface conditions.

In the drawing which accompanies this specication:

Fig. 1 is a side elevational view of a sanding machine including a discholder embodying the subject improvement;

Fig. 2 is a top plan view, partly in section, of the improved discholder, on a larger scale th'an Fig. 11

Fig. 3 is a. sectional view of the disc holder taken along the plane ofthe axis of rotation thereof; and

Fig. 4 is an enlarged detail view depicting the 2 Ita is indicatedfabric reenforcement for the ring or table I6.

Hub I4 includes a cup-shaped member 20 hav-A ing an outwardly directedflange 2| and carries an internally threaded sleeve 22 by means of whichthe holder can be detachably connected to drive-shaft Il of the machine.Sleeve 22 may be brazed, Welded or otherwise firmly secured to member 20or it may be cast or forged integrally therewith, Hub I4 also includes adriven member 23 disposed in co-axial alignment with member 20 andhaving an external flange 24. A depending threaded stud 25 is brazed orotherwise novel construction by which the desired hub flexibility isachieved.

Referring to Fig. 1, the sanding machine there shown is a portable toolcomprising a motor I0 having a suitable built-in right angletransmission including a drive-shaft I I to which the abrasive dlscholder I2 is detachably connected-the drive-shaft being provided with athreaded end for that purpose.

The holder I2 with attached abrasive disc I3 is shown in detail in Figs.2-4 inclusive.

The major components of the disc holder are a hub I4, an annular disc I5carried by the hub and concentric therewith, a molded hard rubber ringI6 generally referred to as a pad, a pair of superposed backing discs I1and I8, 'and a flanged nut lIii which serves to secure the abrasive discI3 and backing discs I1, IB to the holder. At

ilrmly attached to. member 23 in axial alignment with sleeve 22 and forma part of the hub. Nut I9 is threaded onto stud 25 and has a thinslightly convexed head or iiange I9a which bears against the face ofabrasive disc I3. The abrasive disc, together with backing plates I1,I8, are detachable from the holder by removing nut I9 from stud 25.

Flange 2| of member 2|l conveniently is provided `with six equallyspaced holes 26 located on a circle concentrically'with the axis of'rotation of the hub, and in these are rigidly secured, as by riveting,six pins 21.

Flange 24 of member 23 is similarly provided with six equally spacedholes 28 which are in registration, individually, with pins 21 and ofsubstantially larger diameter than the pins so that member 23 can rotateslightly relatively to the pins and to member 20.

Likewise, annular disc I5 is provided with six holes by means of whichit is firmly mounted on pins 21 concentrically with the axis of rotationof the holder.l The periphery of disc I5 is embedded in pad I6 andmaintains the latter in concentric relation to the hub. Disc I5 alsoserves to centralize hub member 23.

As shown most clearly in Figs. 3 and 4, there is interposed betweenflange 2| and ilange 24 a resilient spacer in the form of a gasket orwasher 29, preferably of neoprene or other soft rubberlike material; andsimilarly linterposed between flange 24 and disc |5` is a secondresilient spacer in the form of a gasket or washer 30 which also is madeof material such las neoprene The assembly comprising washers 29 and 30,iianges 2| and 24, and disc I5 are secured together because the headedend of each pin bears against a metal washer or ring 3|. The riveting ofpins 21, being performed at the shouldered ends thereof, does not undulycompress the parts which such pins hold in assembly. Spacers 29 and 30may, alternatively, consist each of 'a single annulus or of severalwashers individual to pins 21. s'

Driving power is transmitted from driving member 20 through' pins 21,thence through resilient spacers 29, 30 to the driven member 23, and

thence via stud 25 and nut I9 to abrasive disc I3 and backing plates Il,I8. The central openings in the abrasive disc and backing plates arenon-circular and preferably hexagonal, and the shank of nut I9 is cicorresponding form to fit said openings whereby to provide a positivedriving connection to the abrasive disc.

The resiliency afforded by spacers 29 and 30 permits the abrasive discto yield to a limited extent to any extra hard spots which may beencountered in the surface being worked upon, such for example as weldseams, and this not only reduces the amount of shock felt by theoperator but it also has been found definitely to result in superiorworkmanship-which probably is attributable to the workman being betterable to steady the machine against shock-producing .conditions and tominimized nervous strain.

Whatever the correct explanation may be, the fact remains that workmenexpress a distinct preference for disc holders constructed in accordancewith the present invention, and it is a demonstrated fact that, on thewhole, they do distinctly better work with disc holders so equipped.Equipment comprising my improved abrasive disc-holder is especiallyadapted to do fine work when feathering the edges of surface coatings ofmetal finishing enamel and the like.

Having thus illustrated and described my invention, what I claim as newand desire to secure by Letters Patent of the United States is:

1. In an abrasive disc holder, a hub comprising a rst hub member havingan outwardly projecting flange, a second hub member co-axial with saidrst hub member and havingan outwardly projecting flange in face-to-facerelation to the f first-mentioned flange, a plurality of spaced pinsrigidly attached to one of said flanges and each passing loosely throughan opening in the other of said flanges, a cushion ofresilient materialclamped between and separating said nanges and operating as the torquetransmitting medium between said hub members, andmeans for attaching anabrasivedisc to said second hub member. l

2. In an abrasive disc holder, a hub comprising a driving member and adriven member co-axial therewith, said membersy having complementaryflanges, a plurality of parallel pins rigidly connected to one of saidflanges and extending loosely through the other flange, a resilientspacer between said flanges and functioning as a torque transmittingmedium between said members, said pins serving to Vclamp said iiangesagainst said spacer, and means for detachably connecting an abrasivedisc to said driven member co-axlally with said hub.

3. In an abrasive disc holder; a hub comprising a driving member and adriven member coaxial therewith,a plurality of spaced pins rigidlyconnected to one of said members and disposed around the axis ofrotation of said hub and extending parallel to said axis, an annulardisc mounted on said pins concentrically with said hub and projectingoutwardly therefrom, an annular pad carried by said disc, said drivenmember having a flange interposed between said driving member and saiddisc, a first resilient cushioning means interposed between said drivingmember and said flange, a second resilient cushioningmeans interposedbetween said disc and said flange, said rst and second cushioning meansand said flange being clamped by said pins between said driving memberand said disc, and means for detachably connecting an abrasive disc tosaid driven member co-axially with said hub.

4. In an abrasive disc holder, a hub comprising a cup-shaped drivingmember adapted for attachment to a drive-shaft and having an externalflange concentric with its axis of rotation, a plurality of pins securedto said flange and circumferentially spaced in a circle concentric withthe axis of rotation of the hub, said pins extending parallel to saidaxis, an annular disc carried by said pins and extending outwardlytherefrom radially to the hub, a driven member forming a part of saidhub and having an external fl e interposed between the first-mentionedila e and said disc, resilient spacing means interpos d Ibetween saidflanges and embracing said pins, additional resilient spacing meansinterposed between said disc and the flange of said driven member andembracing said pins, thev last-mentioned flange being normally out ofcontact with said pins, said driven member being adapted to rotate to alimited extent relatively to said driving member due to the yieldabilityof said spacing means, said driving and driven members and said disc andspacing means being clamped together by said pins, a threaded studcarried by said driven member co-axially therewith, and a flanged nutco-operative with said stud for detachably securing an abrasive disc tothe holder.

5. In an abrasive disc supporting device, a first liub member and asecond hu'b member, the iirst hub member being adapted to bemechanically connected with a motor for rotation thereby, an abrasivedisc table associated with the second hub member and capable of limitedaxial movement relative thereto but incapable of radial movementrelative thereto, the two hub members being provided with opposedannular surfaces occupying planes transverse to the rotational axis ofthe first hub member, the table and the second hub member being providedwith opposed annular surfaces occupying planes transverse to saidrotational axis, annular cushions of relatively soft yielding materialinterposed between the opposed surfaces of the hub members and betweenthe opposed surfaces of the table and the second hub member, a pluralityof pins by which the Afirst hub member is connected with the table, anda plurality of apertures in the second hub member through which suchpins freely extend with substantial clearance.

6. In an abrasive disc holder a hub comprising a driving member and adriven member co-axial therewith, a plurality of parallel pins rigidlyconnected to one of said members and extending loosely through the othermember, a resilient spacer between said driving member and said drivenmember and functioning as a torque transmitting medium between saidmembers, said pins serving to clamp said driving and driven membersagainst said spacer, and means for detachably connecting an abrasivedisc to said driven member coaxially withsaid hub.

GUSTAV A. OLSEN' REFERENCES CITED The following references are of recordin the file of this patent:

UNITED STATES PATENTS Number Name Date 1,835,573 Ponselle Dec. 8, 19311,933,846 Finnell Nov. 7, 1933 FOREIGN PATENTS Number Country Y Date652,171 ,Germany Oct. 26, 1937

